This invention relates to fiber optic couplings and, more particularly, to an assembly that optically aligns an opto-electronic device, such as a Vertical Cavity Surface Emitting Laser (VCSEL) chip, with a fiber optic coupler upon a heatsink substrate.
Owing to their small size, it is difficult to align opto-electronic devices to fiber optic couplers. The present invention comprises a specialized assembly that eliminates the need for exceptional equipment for aligning an opto-electronic device with the fiber bundles of a fiber optic coupler. The assembly comprises a supporting heatsink substrate for the device. The coupler that is to be aligned with the device is supported upon compliant members, such as elastomers, springs, flexures, etc., disposed within the heatsink substrate. The compliant members allow the coupler to move laterally within a housing. A number of mechanical adjustment devices, such as screws, carried by the housing can be adjusted to position the coupler with respect to the heatsink substrate that carries the device.
A flexible circuit that is attached to the device provides power and/or signals. The emitted light is transmitted through the fiber optic bundle of the coupler to a set of photodetectors plugged into a distal end of the coupler. The adjustment devices on the housing are moved until an acceptable alignment is achieved between the light emitting devices (e.g., lasers) and the fiber optic bundles. Once an optimum alignment is achieved, the device and the coupler are permanently affixed by an epoxy.
One of the unique aspects of this assembly is its ability to provide its own, self-contained alignment capability, without depending on additional complex fixturing.
In U.S. Pat. No. 4,252,407, issued to Bubanko et al on Feb. 24, 1981 for FIBRE-TO-FIBRE CONNECTOR FOR MULTIFIBRE CABLES, a fixture having a number of guide pins and fibre-retaining grooves is illustrated.
In U.S. Pat. No. 5,191,629, issued on Mar. 2, 1993 to Kaiser for LASER MODULE, a metal housing is illustrated in which a laser is supported. The laser is moved perpendicularly to its axis by adjusting screws. An optical waveguide is coaxially centered in the bore, axially adjusted, and then fixed in place.
In U.S. Pat. No. 5,418,872, issued on May 23, 1995 to Osaka et al for OPTICAL CONNECTOR CONNECTING APPARATUS AND OPTICAL CONNECTOR CONNECTING METHOD, an apparatus is illustrated wherein a plurality of fixed optical connectors is mounted in juxtaposition with an optical connector. The connector is moved orthogonally by a number of screw threads to correct its position.
In U.S. Pat. No. 5,696,862, issued to Haur et al on Dec. 9, 1997 for OPTICAL TRANSMITTING AND RECEIVING DEVICE HAVING A SURFACE-EMITTING LASER, a VCSEL is shown emitting light to a transmission fiber and a receiving element through a number of reflecting plates.
In U.S. Pat. No. 5,590,227, issued on Dec. 31, 1996 to Osaka et al for OPTICAL CONNECTOR APPARATUS, an apparatus is illustrated wherein a plurality of fixed optical connectors is mounted in juxtaposition with an optical connector. The connector is moved orthogonally by a number of screw threads to correct its position. A beam is flexed to provide fine positioning.
In U.S. Pat. No. 5,812,258, issued to Pierson on Sep. 23, 1998 for OPTICAL COUPLER AND ALIGNMENT APPARATUS WITH MULTIPLE ECCENTRIC ADJUSTMENTS, two eccentric sleeves are rotated to change either the angle or the location of the axis of one optical component relative to another optical component, for alignment. A bonding agent is introduced between the sleeves to fix the alignment permanently.
In accordance with the present invention, there is provided an optical coupling assembly and method of fabricating same. The optical coupling assembly comprises a heatsink substrate upon which is mounted an opto-electronic device, such as a VCSEL laser emitting element. A flexible circuit is attached to the circuitized device, and provides it with power. An outer housing comprises a number of adjustment devices for positioning a fiber optic coupler with respect to the optical paths. The outer housing also comprises a number of biasing elements that acts against the coupler, and biases it in the Y- and Z-axes. The adjustment devices are manipulated until the fiber optic transmitting elements of the coupler align with the receiving elements. Photodetectors plugged into a distal end of the coupler receive the light from the light transmitting device, and provide a means by which optimum alignment is achieved. A bonding medium is introduced to permanently align and fix the components in the proper orientation.
It is an object of this invention to provide an improved optical coupling assembly.
It is another object of the invention to provide an optical coupling assembly that has built-in alignment components.
It is still another object of the invention to provide such an optical coupling assembly with a heatsink.